Contact-post for electric bells



(No Model.)

F. W. MANGER 8v .0. H. HUEBEL'.

CONTAGT POST FOR ELECTRIC BELLS.

No. 475,783. Patented May 31, 1892.

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UNITED STATES f ATENT Ormcn.

FREDERICK W. MANGER AND OTTO H. HUEBEL, OF BROOKLYN, NEWV YORK.

CONTACT-POST FOR ELECTRIC BELLS.

SPECIFICATION forming part of Letters Patent No. 475,783, dated May 31,1892. Application filed February 29, 1892. Serial No. 23,214. (Nomodel.)

.To all whom it may concern:

Be it known that we, FREDERICK W. MAN GER and OTTO I l. HUEBEL, citizensof the United States, residing in Brooklyn, in the county of Kings andState of New York, have invented certain new and useful Improvements inContact Posts for Electric Bells, &c., of which the following is aspecification.

This invention provides an improved construction applicable to rheotomicelectric bells and other instruments requiring contact-posts orscrew-stops which shall be electricallyinsulated from the base of theinstrument.

The object of the invention is to provide a construction for fastening acontact-post to a base while insulating it therefrom which shall guardagainst and prevent the turning or twisting of the post in the eventthat the fastening thereof is loosened in course of time by theshrinking of the intervening insulatinglayers. Electric bells frequentlybecome inoperative, because the insulating-bushings interposed betweenthe post and base shrink or contract, thereby loosening the connectionof the post to the base which is commonly made by a clamping-screw, sothat the post being thus loosened will be liable, by reason of thevibration to which it is subjected, to turn to one side, so that it nolonger presents the platinized end of the screw to the action of thecontact-sprin g.

The invention also involves certain other improvements in the details ofconstruction and mounting of screw-posts and armatures for electricbells and other instruments.

Figure 1 of the accompanying drawings is a front elevation of ourimproved electric bell. Fig. 2 is a fragmentary transverse sectionthereof, showing the post in elevation. Fig. 3 is a similar transversesection taken through the post. Fig. 4. is a fragmentary elevation ofthe base-plate with the post removed. Figs. 5 and dare fragmentarysections showing modified constructions. Fig. 7 *is an under side viewof the post I). Fig. 8 is an elevation of one of the binding-posts.

Let A designate the base-plate, which may be of cast-iron, as usual; B,the bell; O, the electro-magnet; D, the armature thereof, and ,E thecontact-post;

The base plate A is constructed with a raised projection or wall Ct, towhich the screws of the magnet are fastened in the usual manner, andwith a projecting post b, to which is fastened the end of a leaf-springc, which is made fast to the lower end of the armature, therebyconstituting a sort of pivotal connection between the armature and thepost. A spring 0, conveniently constructed as an extension of the spring0, is carried by the armature, and its tip acts against the platinizedend of the contact-screw (I, held by the post E. So far as described theconstruction is substantially that commonly employed in makingcontinuously-ringing or rheotornic bells.

The post'E in the preferred construction is made of a strip of sheet orplate metal bent into U form, as best shown in Figs. 2 and 3. Its baseis made square and sinks into a recess formed in a raised boss 6 on thebaseplate A. This boss has a broad flat groove f planed out across it,as best shown in Fig. 4, this groove being slightly Widerthan the post,so that it will admit the latter with the added thickness of anintervening layer F of insulating material. The opposite side faces g gof the groove constitute angular shoulders, which embrace between themthe turned-up side edges of the insulating-plate, while these turned-upedges in turn embrace the opposite flat sides h h of the bottom portionof the post. The post is turned down and held in place by afastening-screw G, as usual. Inorder that this screw shall not makemetallic contact with the base A, an insulating-washer t is interposedbetween thehead of the screw and the back of the base, and the hole j,through which the shank of the screw passes, is made considerably largerthan the screw, so as to avoid touching it. To keep the screw exactly inthe center of this hole, the washeri is sunk into a recess 70, formed inthe rear side of the plate, into which recess the washer exactly fits,while the hole in the washer closely embraces the shank of the screw, sothat the washer holds the screw concentrically within the opening andprevents its displacement into contact with the sides thereof, even incase the parts should become loose. Beneath the head of the screw isclamped, as usual, the end of a conducting-wire Z, by which IOCconnection is made between this wire and the contact-screw cl throughthe medium of the fastening-screw G and post E.

When the bell is put together, the screw G, of course, is drawn as tightas possible, so as to closely compress the insulating-plates F and i. Incourse of time, however, by reason of the hot dry air in the room orotherwise,

the insulating-layers gradually shrink and become thinner, whereby theconnection of' the post is loosened. l-leretofore when the post has beenmerely clamped in place, relyin g upon the frictional engagement due tothe tightening of the screw, this loosening of the post has resulted inits eventually working or twisting around rotatively until itscontact-screw no longer presents its platinized tip to the spring 0,whereupon the bell usuallybecomesinoperative. Our improved constructioneffectually cures this defect, since, although the fasteningpost maybecome loose, the .post'cannot turn, because it is made with a squarebase having angular-shoulders -71. h embraced through themedium of theinsulation between the angular faces or shoulders g g of the groove inthe boss.

Heretofore it has been necessary to place a tubular insulating sheath orring around the shank of the screw in the hole j to prevent contactbetween the screw and the base. WVe avoid this trouble by providing thebase with a recess 70, which receives a washer 2' and en-. ables thelatter to hold the screw G concen tricall-y within the holej.

The :U-shaped post "E(shown-in Figs. 2 and 3) is a simple, cheap, andconvenient con struction, and enables a set-nut to be applied to thescrew d between the limbs of the post.

An angular set-nut m is shown in Fig. 2, 3

screwed against one limb, While a milled setnut m is shown in Fig. 3,screwed against the other limb. By thus arranging the set-nut within thebifurcation of thepost less room is taken, so that the screw d may bemade shorter thanwould otherwise be necessary.

Fig. 5 shows a modification wherein the screw-post (here lettered E) ismade as a solid casting of brass turned up, its base 7i being block Fwhile the lower portion of the insulating-block is embraced by theopposite shoulders of the channel in the boss e on the plate A, in themanner first described.

Our improved construction of mounting of contact-post'is not limited inits application to electricbells, as it may be used wherever acontact-post is mounted on but insulated In this from a base-plate. Forexample, it may be applied to telegraph-relays.

Our invention is also applicable to other posts than merelycontact-posts. It may, for example, be applied to binding-posts forattaching wires. Fig. 8 shows its application to the insulatedbinding-post H in Fig. 1, which is of ordinary construction, except thatthe base flange or foot 71 thereof is squared or flattened'at its sides,as at hin Fig. 5,and is drawn into a channel in a boss 6 with anintervening insulation F vhaving its edges turned up between the sidesof the channel and the squared sides of the foot of the post, as shown.

Our invention also provides an improved means of attaching theleaf-springc to the post I). This post is made with an angular recessZ), into which is fastened a clampingplate 0', drawn to place by a screwa. spring 0 is formed with a double bond, and is laid into the recess 1)and drawn tightlyinto this recess by the application of theclamping-plate c. A very strong and secure fastening is thusprovided,since the elasticity'of the spring exerts a suflicient thrustagainst the clamping-plate to effectually lock the screwand prevent itsunscrewing.

We claim as our invention the followingdefined novel features,substantially ashereinbefore specified, namely:

1. The combination, with a base-plate and conducting-post, of anintervening insulation and means for preventing the post from turning,consisting of angular shoulders on-the base-plate and post engaging theintervening insulation.

2. The combination, with a base-plate and conducting-post,of anintervening insulation and means for preventing the post from turning,consisting of opposite shoulders on the base engaging the sides of theinsulation and opposite shoulders on the post engaged by the sides ofthe insulation.

3. The combination, with a base-plate, of a raised boss formed with anangular groove or channel, a conducting-post formed atits bottom withangular shoulders, and an intervening insulation having angular sidesengaged by said channel in the boss and saidshoulders on the post,respectively, in order to prevent the post from turning.

t. The combination, with a base-plate having a raised boss formed withan angular channel, of aconducting-post having'a square base enteringsaid channel and an intervening insulation having angularly upturnededges embraced by the sides of the channel and embracing the base of thepost.

5. The combination, with a base-plate, of a bifurcated contact-postfastened to said plate and a contact-screw screwing through the twolimbs of the post.

6. The combination, with a base-plate,of a bifurcated contact-postfastened to said plate, a contact screw screwing through the two limbsof the post, and a set-nut engaging the screw and arranged in thebifurcation of In Witness whereof we have hereunto signed the post. ournainesin the presence of two subscribing IO 7. In an electric bell, avibrating armature, witnesses. a leaf-spring 0,011 which itis mounted,abase- FREDERICK W. MANGER. 5 plate havinga post I), formed with anangu- OTTO H. HUEBEL.

lar recess 1), and a fastening-plate 0, enter- WVitn essses: ing saidrecess and clamping said springinto GEORGE II. FRASER,

the angular space between. CHARLES K. FRASER.

